An airbag and a seat belt are safety apparatuses that protect drivers or passengers from impact when an accident occurs.
The airbag is installed at the front or side of a driver's seat. When a signal from a front collision sensor or a side collision sensor is received, is determined whether or not to inflate the airbag according to impact amount of the collision. The airbag is inflated if the impact amount satisfies a threshold value. The threshold value is preset when manufacturing the airbag.
Since the threshold value is preset as a fixed value, the airbag may not be appropriately inflated. In other words, the airbag may be inflated with insignificant impact and thus a secondary accident such as injury of driver or repair cost occurs.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.